Asteroid Crisis: Star Challengers Book 3 Read Online Free PDF Page B

the names of the planets—Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.”
    “Poor Pluto,” Dyl said, “it used to be considered a planet, but it got demoted. Now it’s called a ‘dwarf planet’—probably just a huge chunk of rock and ice in a long-term orbit.”
    Zota pointed to a large gap that separated the inner four rocky planets from the outer four gas giants. “What we’re most interested in at the moment are the asteroids, right here between Mars and Jupiter.” He touched a keyboard on the controlling computer, and all the planets in the solar system diagram began circling the Sun. The inner ones moved faster, while the outer planets crawled along. The asteroids, a flurry of tiny pinpoints, looked like a swarm of fireflies.
    “Unlike the major planets, asteroids cannot be seen with the naked eye. It wasn’t until 1801 that the first asteroid was discovered by the Italian astronomer Giuseppe Piazzi. At first he thought it was a new comet, but it moved more like a planet. He named it Ceres, after the Roman goddess of agriculture.” Zota indicated the blur of dots. “Amateurs, astronomers, and space telescopes have identified several hundred thousand now, many of them in stable orbits. Some asteroids, however, are erratic and the majority aren’t well cataloged.” The commander shook his head. “In your time, people don’t consider it a very high priority.”
    “I do,” King said. “That’s why I spent so much time scanning star charts with Dr. Wu on the Moon, and Dr. d’Almeida aboard the space station, sir. We detected three that had moved out of their known orbits. Asteroids are hard to find because they’re so small.”
    “Yes,” Zota said. “The large ones are usually fifty to a hundred miles in diameter, and perhaps thirty of them are larger than that. But the vast majority are only a mile or two across—barely a dust speck in the solar system. If we could gather all known asteroids together into a single lump, the total mass would still be smaller than the Earth’s Moon.”
    “If they’re so small, why are we worried about them?” Dyl had taken out his perennial note cards and was busily scribbling down the data Commander Zota recited.
    “Pfft! ‘Small’ is a relative term, Junior,” Song-Ye said. “I certainly wouldn’t want a fifty-mile-wide boulder hitting me on the head.”
    Tony gave a nervous laugh. “I wouldn’t even want a one-mile boulder hitting my head.”
    “You saw the craters made by falling meteorites on the Moon,” Zota said. “And those were tiny pebbles compared to these. The Earth is moving in its orbit, the asteroids are moving; all the planets are constantly circling the Sun. Over the billions of years since the solar system formed, occasional accidents have happened, orbits cross. We know some asteroids come very close to Earth, but even when an asteroid crosses our planets orbit, we don’t have to worry about a collision unless the planet and asteroid are in exactly the same place at exactly the same time.”
    “Right,” JJ said. “Just because two streets intersect, that doesn’t mean two random cars on those streets are going to smash into each other.”
    King pondered the diagram. “It’s like a cosmic chess game. Those altered asteroid orbits aren’t an accident or coincidence. The Kylarn specifically aimed the asteroids.”
    “And if no one was looking, it would be very easy for one of those rocks to slip through unnoticed,” JJ said. “We wouldn’t have any idea until it actually hit us.”
    “Didn’t an asteroid impact cause the extinction of the dinosaurs?” Song-Ye asked.
    “Yes, scientists believe that sixty-five million years ago an asteroid struck our planet, estimated to be only about ten kilometers, or six miles, across. A relatively small asteroid, and yet that one strike wiped out not only the dinosaurs, but three-quarters of all the species that were alive then. That should tell you how much energy